JPH06325704A - Projection type display - Google Patents

Abstract

PURPOSE:To improve the focusing property by eliminating a centering magnet from a deflecting means. CONSTITUTION:In a green projection picture tube of projection picture tubes 1 of red, green, and blue, a centering magnet is eliminated while a convergence coil 3 of a deflecting means 5 is left as it is. While a desired part of a raster can be moved by feeding a correcting current to the coil 3, the whole body of the raster can be moved by the magnetic field of the magnet in the centering magnet. Therefore, by eliminating the centering magnet, the full length in the axial direction of the projection picture tube of an installed deflecting means can be reduced, and an electromagnetic focus unit 7 can be approached to the tube surface of the projection picture tube 1. As a result, since a magnetic field lens formed by the unit 7 can be made in a low multiplying factor, the focusing property of the tube surface of the green projection picture tube can be improved, and accordingly, the focus property of a projection type display can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display, and more particularly to a projection display with improved focus performance on the surface of a projection tube.

[0002]

2. Description of the Related Art A projection display displays an image by projecting an image of a red, green or blue projection tube surface onto a screen.

FIG. 2 shows a general electromagnetic focusing projection tube used in a conventional projection display. In FIG. 2, 1 is a projection tube, 2 is a deflection yoke, 3 is a convergence coil, 4 is a fitting for fixing the deflection means, 6 is a deflection means, 7 is an electromagnetic focusing unit, 8 is an alignment magnet, 9 is a centering magnet, The deflection means 6 is composed of a deflection yoke 2, a convergence coil 3 and a centering magnet 9, and is fixed to the projection tube 1 by a mounting member 4.

In the projection type display, in order to form red, green and blue images on a screen (not shown), the position and shape of the raster on each projection tube surface is corrected and the projection tubes are corrected. This is done by applying a correction current to the centering magnet 9 and the convergence coil 3 of the deflection means 6 mounted on the.

By the way, the focusing performance of the projection display is almost determined by the focusing performance of the tube surface of the green projection tube. This is because human vision has different sensitivities depending on colors. Therefore, to improve the focusing performance of the surface of the projection tube for green over red and blue,
This will improve the focus performance of the projection display.

Therefore, in order to improve the focusing performance of the surface of the green projection tube, for example, the projection display described in Japanese Patent Publication No. 63-5854 has adopted the following method.

That is, the green projection tube is formed by the electromagnetic focusing unit 7 by removing the convergence coil 3 from the installed deflection means 6 and moving the electromagnetic focusing unit 7 closer to the projection tube tube surface by that much. The magnetic field lens has a low magnification, and the focusing performance of the green projection tube surface has been improved. In addition, convergence adjustment is
A correction current is applied to each of the convergence coils 3 attached to the red and blue projection tubes, the red image and the blue image are independently moved in the horizontal and vertical directions, and they are superimposed on the green image. It was

[0008]

However, the above-mentioned proposed examples have the following problems. That is, when the convergence coil 3 is deleted from the green projection tube, the convergence correction may not be possible depending on the shape of the projection tube, and in such a case, there is a problem that an accurate raster cannot be produced. Further, even if the convergence correction can be performed, there is a problem that a finer correction cannot be performed because the convergence coil 3 is not provided, and thus a better image cannot be obtained.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a projection display with improved focus performance by improving the focus performance of the surface of the green projection tube. .

[0010]

In order to achieve the above-mentioned object, in the present invention, among the red, green and blue projection tubes, the green projection tube is equipped with a deflection coil which is a convergence coil. The centering magnet was deleted as it was.

[0011]

In the deflection means mounted on the projection tube, the convergence coil can move an arbitrary portion of the raster by passing a correction current, whereas the centering magnet can move the entire raster by the magnetic field of the magnet. .

By the way, in the projection display, as shown in FIG. 3, the red projection tube 14 and the blue projection tube 16 are arranged on the left and right, and the green projection tube 15 is arranged on the center. Therefore, regarding the red projection tube 14 and the blue projection tube 16,
Due to the large misalignment of the raster, when performing convergence correction, only the correction by the convergence coil that can move any part of the raster will increase the load on the convergence coil, and therefore the centering that can move the entire raster. Correction by magnet is necessary.

However, with respect to the green projection tube 15, there is almost no vertical or horizontal misalignment of the raster, and when performing the convergence correction, the convergence correction amount is the red projection tube 14,
Since the number is smaller than that of the blue projection tube 16, the correction by the centering magnet that can move the entire raster is not so necessary, and only the correction by the convergence coil that can move any part of the raster is required.
I can deal with it enough.

Therefore, as in the present invention, even if the centering magnet is removed from the deflection means to be mounted on the green projection tube 15, the convergence correction can be performed without any trouble, and the convergence coil is still present. Therefore, finer correction can be performed.

Therefore, according to the present invention, since the centering magnet is removed, the total length of the deflection means to be mounted in the axial direction of the projection tube tube can be shortened. Since it is possible to approach the tube surface, and as a result, it is possible to reduce the magnification of the magnetic field lens formed by the electromagnetic focusing unit, it is possible to improve the focusing performance of the green projection tube tube surface, and, by extension, It is possible to improve the focus performance of the projection display. In addition, in FIG. 3, 17 is a red projection lens, 18 is a green projection lens, 19 is a blue projection lens, and 20 is a screen.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below.
FIG. 1 is a side view showing an electromagnetic focusing type projection tube used in a projection type display as one embodiment of the present invention. In FIG. 1, reference numeral 5 is a deflecting means, and other same constituent elements as those in FIG. 2 are designated by the same reference numerals.

In this embodiment, in order to improve the focus performance of the projection type display, in order to improve the focus performance of the surface of the green projection tube, among the red, green and blue projection tubes, the green projection tube is As the deflecting means, the deflecting means 5 from which the centering magnet 9 is removed is attached. That is, as described above, the centering magnet 9
Since the centering magnet mounting portion is eliminated by deleting the, the total length in the axial direction of the projection tube tube of the deflecting means 5 can be shortened by the width A occupied by the centering magnet mounting portion shown in FIG. As a result, the electromagnetic focusing unit 7 can be brought closer to the projection tube surface by the length A.

FIG. 4 is an explanatory view showing the position of the magnetic field lens formed by the electromagnetic focusing unit 7 of FIG. 1 in comparison with the position of the magnetic field lens formed by the electromagnetic focusing unit 7 of FIG.

In FIG. 4, the electron beam emitted from the electron gun 10 is focused on the projection tube surface 13 by the magnetic field lenses 11 and 12 formed by the electromagnetic focusing unit 7. Here, the magnetic field lens 11 formed by the electromagnetic focusing unit 7 according to the present embodiment in FIG. 1 is brought closer to the projection tube tube surface 13 by the length A than the magnetic field lens 12 formed by the electromagnetic focusing unit 7 in FIG. And the magnetic field lens 11
And the magnification of the magnetic field lens 12, the distance from the projection tube tube surface 13 to the magnetic field lens 12 is a, and the distance from the magnetic field lens 12 to the electron gun 10 is b,

[0020]

## EQU1 ## (a / b)> (a−A) / (b + A).

Therefore, according to the present embodiment, the deflecting means 5 of the green projection tube in which the centering magnet 9 is removed is omitted.
By mounting, the reduction of the magnification of the magnetic field lens 11 formed by the electromagnetic focusing unit 7 can be realized, and the focusing performance of the tube surface of the green projection tube is improved. Therefore, it is possible to improve the focus performance of the projection display.

[0022]

According to the present invention, with respect to the green projection tube, by removing the centering magnet from the deflection means to be mounted, the total length of the deflection means to be mounted in the axial direction of the projection tube can be shortened accordingly. Therefore, the electromagnetic focusing unit to be mounted can be brought close to the projection tube surface. Therefore, as a result, the magnetic field lens formed by the electromagnetic focusing unit can be reduced in magnification, so that the focusing performance of the surface of the green projection tube can be improved and, in turn, the focusing performance of the projection display can be improved. Can be improved.

Even if the centering magnet is removed from the attached deflection means, the convergence correction can be performed without any trouble, and since the convergence coil is still present, finer correction can be performed.

[Brief description of drawings]

FIG. 1 is a side view showing an electromagnetic focusing projection tube used in a projection display as one embodiment of the present invention.

FIG. 2 is a side view showing a general electromagnetic focusing type projection tube used in a conventional projection display.

FIG. 3 is a conceptual diagram showing an arrangement of projection tubes in a general projection display.

4 is an explanatory view showing the position of a magnetic field lens formed by the electromagnetic focusing unit 7 of FIG. 1 in comparison with the position of a magnetic field lens formed by the electromagnetic focusing unit 7 of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Projection tube, 2 ... Deflection yoke, 3 ... Convergence coil, 4 ... Mounting metal fittings, 5, 6 ... Deflection means, 7 ... Electromagnetic focusing unit, 8 ... Alignment magnet, 9 ... Centering magnet, 10 ... Electron gun, 11, 12 ... Magnetic field lens, 13 ... Projection tube surface, 14 ... Red projection tube, 15 ... Green projection tube, 16 ... Blue projection tube, 17 ... Red projection lens, 18 ... Green projection lens, 19 ... Blue projection lens, 20 ... screen.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keiji Ito 1-1 Sanyo-cho, Daito-shi, Osaka Sanyo Electric Co., Ltd.

Claims (1)

[Claims] 1. A red projection tube for displaying a red image, a green projection tube for displaying a green image, a blue projection tube for displaying a blue image, and each image displayed by each projection tube are enlarged. A projection lens for projecting, and a screen on which images magnified and projected by the projection lens are combined with each other,
Each of the projection tubes is formed by a deflection means including a deflection yoke, a convergence coil and a centering magnet for deflecting an electron beam emitted from an electron gun, and a coil or a magnet for converging the electron beam. In the projection type display, the centering magnet is removed from the deflection means to be mounted on the green projection tube of the projection tubes, the electromagnetic focusing unit being arranged side by side from the projection tube surface side. By doing so, the mounted electromagnetic focusing unit is brought close to the tube surface of the projection tube.